洛谷 P3384 【模板】树链剖分

#include<cstdio>
#include<algorithm>
#define ll long long
#define N 200010
using namespace std;
struct node{int v,fr;}e[N<<2];
int n,m,r,p,a[N],tail[N],cnt=0,tot=0;
int siz[N],fa[N],son[N],zf[N],dep[N];
int dfn[N],t[N<<4],lazy[N<<4],tt,x,y,z;

inline int read()
{
	int x=0; char c=getchar();
	while (c<'0' || c>'9') c=getchar();
	while (c>='0' && c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return x;
}

void add(int u,int v) {e[++cnt]=(node){v,tail[u]}; tail[u]=cnt;}

void dfs1(int x)
{
	siz[x]=1;
	for (int p=tail[x],v;p;p=e[p].fr)
		if ((v=e[p].v)!=fa[x])
		{
			dep[v]=dep[x]+1,fa[v]=x,dfs1(v),siz[x]+=siz[v];
			if (siz[son[x]]<siz[v]) son[x]=v;
		}
}

void ad(int x,int l,int r,int f,int in)
{
	if (l==r) {t[x]=in; return;}
	int mid=l+r>>1;
	if (f<=mid) ad(x<<1,l,mid,f,in);
	else ad(x<<1|1,mid+1,r,f,in);
	t[x]=t[x<<1]+t[x<<1|1];
}

void dfs2(int x,int gf)
{
	dfn[x]=++tot,ad(1,1,n,tot,a[x]),zf[x]=gf;
	if (!son[x]) return;
	dfs2(son[x],gf);
	for (int p=tail[x],v;p;p=e[p].fr)
		if ((v=e[p].v)!=fa[x] && v!=son[x]) dfs2(v,v);
}

void update(int x,int l,int r)
{
	if (!lazy[x]) return;
	t[x]=(t[x]+(ll)(r-l+1)*lazy[x]%p)%p;
	if (l<r) lazy[x<<1]=(lazy[x<<1]+lazy[x])%p,lazy[x<<1|1]=(lazy[x<<1|1]+lazy[x])%p;
	lazy[x]=0;
}

void insert(int x,int l,int r,int fl,int fr,int ins)
{
	if (fl==l && fr==r)
	{
		lazy[x]=(lazy[x]+ins)%p;
		update(x,l,r);
		return;
	}
	update(x,l,r);
	int mid=l+r>>1;
	if (fr<=mid) insert(x<<1,l,mid,fl,fr,ins);
	else if (fl>mid) insert(x<<1|1,mid+1,r,fl,fr,ins);
	else insert(x<<1,l,mid,fl,mid,ins),insert(x<<1|1,mid+1,r,mid+1,fr,ins);
	update(x<<1,l,mid),update(x<<1|1,mid+1,r);
	t[x]=(t[x<<1]+t[x<<1|1])%p;
}

void change(int x,int y,int z)
{
	z%=p;
	while (zf[x]!=zf[y])
	{
		if (dep[zf[x]]<dep[zf[y]]) swap(x,y);
		insert(1,1,n,dfn[zf[x]],dfn[x],z);
		x=fa[zf[x]];
	}
	if (dep[x]>dep[y]) swap(x,y);
	insert(1,1,n,dfn[x],dfn[y],z);
}

int query(int x,int l,int r,int fl,int fr)
{
	update(x,l,r);
	if (l==fl && r==fr) return t[x];
	int mid=l+r>>1;
	if (fr<=mid) return query(x<<1,l,mid,fl,fr);
	else if (fl>mid) return query(x<<1|1,mid+1,r,fl,fr);
	else return (query(x<<1,l,mid,fl,mid)+query(x<<1|1,mid+1,r,mid+1,fr))%p;
}

int gans(int x,int y)
{
	int s=0;
	while (zf[x]!=zf[y])
	{
		if (dep[zf[x]]<dep[zf[y]]) swap(x,y);
		s=(s+query(1,1,n,dfn[zf[x]],dfn[x]))%p;
		x=fa[zf[x]];
	}
	if (dep[x]>dep[y]) swap(x,y);
	return (s+query(1,1,n,dfn[x],dfn[y]))%p;
}

int main()
{
	freopen("P3384.in","r",stdin);
	freopen("P3384.out","w",stdout);
	n=read(),m=read(),r=read(),p=read();
	for (int i=1;i<=n;i++) a[i]=read();
	for (int i=1,u,v;i<n;i++)
		u=read(),v=read(),add(u,v),add(v,u);
	dfs1(r),dfs2(r,r);
	while (m--)
	{
		tt=read();
		if (tt==1) x=read(),y=read(),z=read(),change(x,y,z);
		else if (tt==2) x=read(),y=read(),printf("%d
",gans(x,y));
		else if (tt==3) x=read(),y=read(),insert(1,1,n,dfn[x],dfn[x]+siz[x]-1,y);
		else x=read(),printf("%d
",query(1,1,n,dfn[x],dfn[x]+siz[x]-1));
	}
	return 0;
}